WO2006120932A1

WO2006120932A1 - Light guide and image reader

Info

Publication number: WO2006120932A1
Application number: PCT/JP2006/308943
Authority: WO
Inventors: Makoto Ikeda; Hiroyuki Nemoto; Takashi Kishimoto; Takeshi Ishimaru; Hirohiko Iwase; Hidemitsu Takeuchi; Tomihisa Saito
Original assignee: Nippon Sheet Glass Company, Limited
Priority date: 2005-05-12
Filing date: 2006-04-28
Publication date: 2006-11-16
Also published as: TW200700783A; US20090218525A1; JPWO2006120932A1; CN101175945A; US7812304B2; KR20080012893A

Abstract

[PROBLEMS] To provide a light guide in which unevenness in color does not take place even at a part close to the incident face. [MEANS FOR SOLVING PROBLEMS] A rod-like light guide (3) is produced by injection molding transparent resin such as acryl, and its surface comprises an exit face (3a), a bottom face (3b), right and left side faces (3d, 3c) and end faces (3e, 3f). One end face (3e) opposes a light emitting unit (10), and a light scattering pattern for scattering incident light from the end face (3e) is formed on the bottom face (3b). The light scattering pattern provides pattern shapes different between a portion close to the end face (3e) as the incident face and a portion separated from the end face (3e). The light scattering pattern (11) formed at the portion close to the incident face consists of a large number of fine hemispherical recesses whereas the light scattering pattern (12) separated from the incident face consists of triangular grooves or half-cut tubular grooves, and the axial direction of these triangular grooves or half-cut tubular grooves is the width direction (sub-scanning direction) of the pattern-forming bottom face (3b).

Description

明細書 Specification

導光体及び画像読取装置 Light guide and image reading apparatus

発明の属する技術分野 TECHNICAL FIELD OF THE INVENTION

[0001] 本発明は、画像読取装置などに用いる導光体およびこの導光体を備えた画像読取装置に関する。 The present invention relates to a light guide used for an image reading device and the like and an image reading device provided with the light guide.

背景技術 Background art

[0002] ファクシミリ、複写機、スキャナ装置などの画像読取装置には、原稿にライン状の光を照射する棒状導光体を組み込んだ照明装置と、原稿力の反射光をラインィメージセンサに集光せしめるレンズアレイとを備えたイメージセンサが組み込まれている。 [0002] Image reading devices such as facsimiles, copiers, and scanners illuminate a manuscript with a bar-shaped light guide that irradiates a document with line-shaped light, and the reflected light of the manuscript power is condensed on a line image sensor. An image sensor including a lens array is incorporated.

[0003] 棒状導光体を組み込んだ照明装置は、一端に LED等の発光手段を取付け、この発光手段からの光を棒状導光体の端面から内部に導入し、棒状導光体内を伝播する光を棒状導光体の側面に形成した光散乱パターンにて散乱せしめ、この散乱した光を棒状導光体の出射面から原稿に向けて照射するようにして、る。 [0003] An illumination device incorporating a rod-shaped light guide has light emitting means such as an LED attached to one end, introduces light from this light-emitting means into the inside from the end surface of the rod-shaped light guide, and propagates through the rod-shaped light guide. The scattered light is scattered by a light scattering pattern formed on the side surface of the rod-shaped light guide, and the scattered light is irradiated from the exit surface of the rod-shaped light guide toward the original.

[0004] そして、前記棒状導光体は一般に角棒状をなし、前記光散乱パターンはシルクスクリーン印刷によって白色塗料を導光体の側面に転写することで形成して、る。（特許文献 1) [0004] The rod-shaped light guide generally has a rectangular bar shape, and the light scattering pattern is formed by transferring a white paint onto the side surface of the light guide by silk screen printing. (Patent Literature 1)

[0005] 上記白色塗料をプリントする光散乱パターンの作製方法は、プリント工程が必要になるためコストアップにつながり、光散乱パターンの特性のばらつきも生じる。そこで、特許文献 2に開示されるように、導光体を射出成形する金型キヤビティに予め凹凸部を形成しておき、この凹凸部を棒状導光体の側面に転写して光散乱パターンとすることが提案されている。 [0005] The method for producing a light scattering pattern for printing the white paint requires a printing process, which leads to an increase in cost and also causes variations in characteristics of the light scattering pattern. Therefore, as disclosed in Patent Document 2, an uneven portion is formed in advance in a mold cavity for injection molding the light guide, and the uneven portion is transferred to the side surface of the rod-shaped light guide to obtain a light scattering pattern. It has been proposed to do so.

[0006] 特に、特許文献 2では凹凸部として三角溝を選択し、この三角溝の軸 (長さ方向）を導光体側面の幅方向と一致させるか、幅方向に対して所定角度だけ斜めにして、る特許文献 1 :特開平 8— 163320号公報 [0006] In particular, in Patent Document 2, a triangular groove is selected as the concavo-convex portion, and the axis (length direction) of this triangular groove coincides with the width direction of the side surface of the light guide or is inclined by a predetermined angle with respect to the width direction. Patent Document 1: JP-A-8-163320

特許文献 2：特開 2001— 242322号公報 Patent Document 2: Japanese Patent Laid-Open No. 2001-242322

発明の開示発明が解決しょうとする課題 Disclosure of the invention Problems to be solved by the invention

[0007] 図 12は光散乱パターンとして三角溝を導光体側面の幅方向と一致させて形成した導光体 (特許文献 1の第 1実施例)の主走査変位と光強度との関係を各色ごとに示したグラフであり、（a)は原稿の浮き量力0mm、（b)原稿の浮き量が 3mm、（c)は原稿の浮き量力 SOmmと 3mmの場合の光強度比を示す。 FIG. 12 shows the relationship between the main scanning displacement and the light intensity of a light guide (first embodiment of Patent Document 1) in which triangular grooves are formed as light scattering patterns so as to coincide with the width direction of the side of the light guide. It is a graph shown for each color, where (a) shows the light intensity ratio when the document lift is 0 mm, (b) the document lift is 3 mm, and (c) shows the light intensity ratio when the document lift is SOmm and 3 mm.

[0008] 図 12 (a)から、 RGBの各 LEDチップからの光強度は、主走査変位 10mm以上では略一致し、 10mmより入射端面によった領域では青色 (B)は他の色 (G, R)に比ベて弱ぐまた各色とも端面に近づく程、光強度は弱くなつていくことが分かる。 [0008] From Fig. 12 (a), the light intensity from each RGB LED chip is approximately the same when the main scanning displacement is 10 mm or more, and blue (B) is the other color ( It can be seen that the light intensity becomes weaker as it approaches the end face for each color.

[0009] 一方、図 12 (b)から、主走査変位 15mm近傍において、青色 (B)と赤色 (R)が異常に光強度が高くなり、 10mmより入射端面によった領域では緑色 (G)の光強度が青色 (B)と赤色 (R)に比較して高、ことが分かる。また図 12 (c)からも主走査変位 15 mm近傍にける青色 (B)と赤色 (R)の異常な盛り上がりがあることが分かる。 On the other hand, from FIG. 12 (b), blue (B) and red (R) have unusually high light intensity near the main scanning displacement of 15mm, and green (G) in the region depending on the incident end face from 10mm. It can be seen that the light intensity of is higher than that of blue (B) and red (R). Also, from Fig. 12 (c), it can be seen that there is an abnormal rise of blue (B) and red (R) near the main scanning displacement of 15 mm.

[0010] このように、主走査変位 15mm近傍において特定の色、例えば青色 (B)と赤色 (R) の光強度に異常値があると、主走査変位 15mm近傍においては青色 (B)と赤色 (R) が強調され、色ムラとして観察されること〖こなる。 [0010] In this way, if there is an abnormal value in the light intensity of a specific color, for example, blue (B) and red (R) in the vicinity of the main scanning displacement of 15 mm, blue (B) and red in the vicinity of the main scanning displacement of 15 mm. (R) is emphasized and is observed as uneven color.

課題を解決するための手段 Means for solving the problem

[0011] 上記課題を解決するため本発明は、棒状をなす導光体として、一端面を入射面とし、一側面を出射面とし、他の側面に前記出射面に向力つて光を反射せしめる光散乱ノターンが設けられ、この光散乱パターンは凹部または凸部で構成され、この光散乱ノターンのうち前記入射面の近傍部分ではパターン形状を出射面以外に向力つても反射する角度依存性のない形状とされ、前記入射面から離れた部分ではパターン形状を出射面に向かって反射する角度依存性のある形状とされた構成とした。 In order to solve the above-described problems, the present invention provides a rod-shaped light guide that has one end surface as an incident surface, one side surface as an output surface, and the other side surface that reflects the light by directing the output surface. A light scattering pattern is provided, and the light scattering pattern is composed of a concave portion or a convex portion. Of the light scattering pattern, in the vicinity of the incident surface, the pattern shape is reflected even if it is directed to other than the exit surface. The configuration is such that the pattern shape is an angle-dependent shape that reflects toward the exit surface at a portion away from the entrance surface.

[0012] 本発明において棒状とは、端面形状が四角形、五角形、六角形などの角棒状を指す力側面全体を曲面或いは側面の一部を曲面とし、出射面と光散乱パターンを形成する底面のみが平面であるものも含む。また端面形状が六角形のものとしては、両側面と底面との間に底面で反射した光を出射面に向けて反射する角度の平坦状面取り部が形成されたものが挙げられる。 [0012] In the present invention, the term "rod" refers to a force that indicates the shape of a square bar such as a quadrangle, pentagon, or hexagonal end face. This includes those in which only the bottom surface is flat. In addition, examples of the hexagonal end surface include those in which a flat chamfered portion having an angle that reflects light reflected from the bottom surface toward the output surface is formed between both side surfaces and the bottom surface.

[0013] また、角度依存性 (方向依存性)とは導光体内を伝播する光のうち、導光体の長さ方向と平行な光が光散乱パターンに当たった際に、反射する方向が決まっている場合を角度依存性があるとし、反射する方向が決まっていない場合を角度依存性がないとする。例えば、光散乱パターンとして三角溝または半割円筒溝は反射する方向が決まって、るので角度依存性があり、半球状凹部や半球状凸部或!、は白色ペイントは反射する方向が決まっていないので角度依存性がないことになる。また、三角溝や半割円筒溝は単一では角度依存性があっても、軸方向が異なるものを組み合わせることで角度依存性がなくなる形状もある。 [0013] In addition, angle dependency (direction dependency) is the length of a light guide among light propagating in the light guide. When light parallel to the direction hits the light scattering pattern, it is assumed that there is angle dependency when the direction of reflection is determined, and there is no angle dependency when the direction of reflection is not determined. For example, as the light scattering pattern, the reflecting direction of the triangular groove or the half-cylindrical groove is determined, so there is an angle dependency, and the reflecting direction of the hemispherical concave part, the hemispherical convex part or! Because there is no angle dependence. In addition, even if a single triangular groove or half-cylindrical groove has an angle dependency, there is a shape in which the angle dependency is eliminated by combining those with different axial directions.

[0014] 更に、入射面の近傍部分とは主走査変位で端面から 50〜70mmまでの範囲を指す。 [0014] Further, the vicinity of the incident surface refers to a range from 50 to 70 mm from the end surface by main scanning displacement.

[0015] そして、本発明にあっては具体的なパターン形状として、導光体一端の入射面の近傍部分の光散乱パターンの形状としては、多数の微細な半球状凹部力なるものが挙げられ、前記入射面力離れた部分の光散乱パターンの形状としては、パターンを形成した側面の幅方向（副走査方向）を軸方向とする三角溝または半割円筒溝が挙げられる。 In the present invention, as a specific pattern shape, as the shape of the light scattering pattern in the vicinity of the incident surface at one end of the light guide, there are a number of fine hemispherical concave forces. Examples of the shape of the light scattering pattern in the part away from the incident surface force include a triangular groove or a half-cylindrical groove whose axial direction is the width direction (sub-scanning direction) of the side surface on which the pattern is formed.

[0016] 前記入射面の近傍部分の光散乱パターンの変形例としては、多数の微細な半球状凹部の密度が、パターンを形成した側面の長さ方向（主走査方向）において異なるものが考えられる。 [0016] As a modification of the light scattering pattern in the vicinity of the incident surface, the density of many fine hemispherical recesses may be different in the length direction (main scanning direction) of the side surface on which the pattern is formed. .

[0017] また入射面の近傍部分の光散乱パターンを構成する多数の微細な半球状凹部としては、連続または分離して形成されるものの何れも含み、特に、半球状凹部の深さを当該半球状凹部がその一部をなす球の直径の 0. 23以上 0. 33以下とするのが好ましい。 [0017] In addition, the numerous fine hemispherical recesses constituting the light scattering pattern in the vicinity of the incident surface include any one formed continuously or separately, and in particular the depth of the hemispherical recesses It is preferable that the diameter of the sphere that the hemispherical concave part forms is not less than 0.23 and not more than 0.33.

[0018] また、入射面の近傍部分の光散乱パターンの変形例としては、導光体側面の幅方向に対し斜め方向を軸方向とする三角溝または半割円筒溝とし、これら互いに隣り合う三角溝または半割円筒溝の軸方向が側面の幅方向を基準として反対方向になる構成が考えられる。 [0018] Further, as a modification of the light scattering pattern in the vicinity of the incident surface, a triangular groove or a half cylindrical groove whose axial direction is an oblique direction with respect to the width direction of the side surface of the light guide is adjacent to each other. A configuration in which the axial direction of the triangular groove or the half cylindrical groove is opposite to the width direction of the side surface is conceivable.

[0019] 本発明の対象には請求項 1乃至請求項 7に記載の導光体を組み込んだ照明装置と、この照明装置力の出射光のうち原稿からの反射光をラインイメージセンサに向けて集光せしめるレンズアレイとを備えた画像読取装置も含まれる。発明の効果 [0019] The subject of the present invention is an illumination device incorporating the light guide according to any one of claims 1 to 7, and the reflected light from the original of the emitted light of the illumination device force is directed to the line image sensor. And an image reading device including a lens array for condensing light. The invention's effect

[0020] 本発明によれば、導光体の側面に形成する光散乱パターンとして、導光体の成形と同時に成形できる凹凸形状とすることで、製作コストを抑えることができ、特に光散乱パターンのうち入射端面に近い部分の光散乱パターン形状を角度依存性のないものとすることで、入射面近傍において特定の色が強調される色ムラを防止でき、また入射端面から離れた部分の光散乱パターン形状を角度依存性のある形状とすることで出射面力出射する光量の低下を防止できる。 [0020] According to the present invention, the light scattering pattern formed on the side surface of the light guide has a concavo-convex shape that can be formed simultaneously with the formation of the light guide, thereby making it possible to reduce the manufacturing cost, and in particular the light scattering. By making the light scattering pattern shape of the pattern close to the incident end face to have no angle dependence, color unevenness in which a specific color is emphasized near the incident face can be prevented, and a part away from the incident end face By making the light scattering pattern shape having an angle dependency, it is possible to prevent a reduction in the amount of light emitted from the exit surface force.

発明を実施するための最良の形態 BEST MODE FOR CARRYING OUT THE INVENTION

[0021] 以下に本発明の実施の形態を添付図面に基づいて説明する。図 1は本発明に係る導光体を組み込んだライン照明装置を用いた画像読取装置の断面図、図 2はライン照明装置の分解斜視図、図 3 (a)は本発明に係る導光体の正面図、（b)は背面図、 ( c)は平面図、（d)は底面図、（e)は左側面図、（f)は右側面図、図 4は本発明に係る導光体の入射面の近傍部分における光散乱パターンの拡大図である。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1 is a cross-sectional view of an image reading apparatus using a line illumination device incorporating a light guide according to the present invention, FIG. 2 is an exploded perspective view of the line illumination device, and FIG. 3 (a) is a light guide according to the present invention. (B) is a rear view, (d) is a bottom view, (e) is a left side view, (f) is a right side view, and FIG. 4 is a light guide according to the present invention. It is an enlarged view of the light-scattering pattern in the vicinity part of the entrance plane of a body.

[0022] 画像読取装置はフレーム (筐体） 1に凹部 la、凹部 lbを形成し、凹部 laの上面は原稿を載置する透明な天板 2で塞ぎ、凹部 la内には棒状導光体 3をケース 4に収めたライン照明装置 5を斜めに固定し、また下方の凹部 lbにはラインイメージセンサ（光電変換素子) 6とその駆動回路 7を備えた基板 8を取り付け、更にフレーム 1内には等倍結像用のレンズアレイ 9を保持して、る。 The image reading apparatus has a recess la and a recess lb formed in a frame (housing) 1. The upper surface of the recess la is closed with a transparent top plate 2 on which an original is placed, and a rod-shaped light guide is placed in the recess la. The line lighting device 5 in which the 3 is housed in the case 4 is fixed obliquely, and a substrate 8 having a line image sensor (photoelectric conversion element) 6 and its driving circuit 7 is attached to the lower concave portion lb, and the frame 1 A lens array 9 for equal magnification imaging is held inside.

[0023] 而して、ライン照明装置 5の出射面から出射した光線にて、天板 2上に載置した原稿を照射し、その反射光をレンズアレイ 9でライン状に配列したイメージセンサ 6に入射せしめる。 Thus, the image sensor in which the original placed on the top 2 is irradiated with the light emitted from the exit surface of the line illumination device 5 and the reflected light is arranged in a line by the lens array 9. Enter 6.

[0024] 前記ライン照明装置 5のケース 4は断面 U字状をなし、ケース 4の開口に棒状導光体 3の出射面 3aが位置するように嵌め込まれている。また、ケース 4の一端には発光ュニット 10が取り付けられ、この発光ユニット 10には青色素子 10a,赤色素子 10b,緑色素子 10cが棒状導光体 3の底面 3bの幅方向中心線からの法線上に沿って等間隔に取り付けられている。 The case 4 of the line illumination device 5 has a U-shaped cross section, and is fitted into the opening of the case 4 so that the emission surface 3a of the rod-shaped light guide 3 is located. Further, a light emitting unit 10 is attached to one end of the case 4, and the light emitting unit 10 includes a blue element 10a, a red element 10b, and a green element 10c from the center line in the width direction of the bottom surface 3b of the rod-shaped light guide 3. They are mounted at regular intervals along the normal.

[0025] 棒状導光体 3はアクリルなどの透明榭脂を射出成形してなり、出射面 3a、底面 3b、左右の側面 3c, 3d及び端面 3e, 3fにてその表面が構成される。そして、一方の端面 3eが前記発光ユニット 10に対向し、底面 3bには前記端面 3eから入射した光を散乱せしめる光散乱パターンが形成されて、る。 [0025] The rod-shaped light guide 3 is formed by injection molding a transparent resin such as acrylic, and its surface is constituted by the emission surface 3a, the bottom surface 3b, the left and right side surfaces 3c, 3d, and the end surfaces 3e, 3f. And one end face 3e faces the light emitting unit 10, and a light scattering pattern for scattering light incident from the end face 3e is formed on the bottom surface 3b.

[0026] 光散乱パターンは入射面としての端面 3eの近傍部分と端面 3eから離れた部分とでノターン形状を異ならせている。尚、本実施例では端面 3eから 60mmの領域を入射面の近傍部分とし、 60mmを超えて他方の端面 3fまでの領域を入射面から離れた部分とする。 [0026] In the light scattering pattern, the no-turn shape is different between the vicinity of the end surface 3e as the incident surface and the portion away from the end surface 3e. In the present embodiment, the region 60 mm from the end surface 3e is the vicinity of the incident surface, and the region beyond 60 mm to the other end surface 3f is the portion away from the incident surface.

[0027] そして、入射面の近傍部分に形成された光散乱パターン 11は、多数の微細な半球状凹部からなり、また入射面力も離れた部分の光散乱パターン 12は、三角溝または半割円筒溝力なり、これら三角溝または半割円筒溝の軸方向はパターンを形成した底面 3bの幅方向（副走査方向）となっている。これら光散乱パターン 11, 12の表面は鏡面仕上げしてもよいし、粗面としてもよい。 [0027] The light scattering pattern 11 formed in the vicinity of the incident surface is composed of a large number of fine hemispherical concave portions, and the light scattering pattern 12 in the portion away from the incident surface force is a triangular groove or a half cylinder. The axial direction of these triangular grooves or halved cylindrical grooves is the width direction (sub-scanning direction) of the bottom surface 3b on which the pattern is formed. The surface of these light scattering patterns 11 and 12 may be mirror-finished or rough.

[0028] 前記光散乱パターン 11となる半球状凹部は入射光線をあらゆる方向に反射するため角度依存性がない形状と言え、前記光散乱パターン 12は入射光線を主に出射面 3aに向けて反射せしめるため角度依存性がある形状と言える。 [0028] The hemispherical concave portion that becomes the light scattering pattern 11 reflects the incident light beam in any direction and can be said to have no angle dependency. The light scattering pattern 12 mainly directs the incident light beam toward the exit surface 3a. It can be said that the shape has an angle dependency because it is reflected.

[0029] 図 5は前記の実施例に示した導光体の主走査変位と光強度との関係を各色ごとに示したグラフであり、（a)は原稿の浮き量力Omm、（b)原稿の浮き量が 3mm、（c)は原稿の浮き量力 SOmmと 3mmの場合の光強度比を示す。 FIG. 5 is a graph showing the relationship between the main scanning displacement and the light intensity of the light guide shown in the above-described embodiment for each color, (a) is the document floating amount force Omm, and (b) is the document. (C) shows the light intensity ratio when the original float height is SOmm and 3mm.

[0030] 図 5 (a)から、 RGBの各 LEDチップからの光強度は、主走査変位 10mm以上では略一致し、 10mmより入射端面に寄った領域では各色とも端面に近づく程、光強度は弱くなつていくことが分かる。特に従来の図 12 (a)と比較すると、共に原稿の浮き量力 SOmmである力本発明の導光体は入射面の近傍部分における各色の光強度が略等しくなつている。このため、本発明の導光体を用いると色ムラが発生し難いと言える。 [0030] From FIG. 5 (a), the light intensity from each of the RGB LED chips is substantially the same when the main scanning displacement is 10 mm or more, and in the region closer to the incident end face than 10 mm, the light intensity becomes closer to the end face for each color. You can see that it ’s getting weaker. In particular, as compared with the conventional FIG. 12 (a), the force of the document floating force SOmm is the same. In the light guide of the present invention, the light intensity of each color in the vicinity of the incident surface is substantially equal. For this reason, it can be said that color unevenness hardly occurs when the light guide of the present invention is used.

[0031] また、図 5 (b)から、原稿の浮き量が 3mmであっても、その波形は図 5 (a)の原稿の浮き量が Ommと殆んど変わらず、同図 (c)から原稿の浮き量が大きくなつても強度比はそれ程変化しないことが分かる。特に、本発明の導光体にあっては従来のように主走査変位が 15mmとなる位置に異常な盛り上りが認められず、本願発明は色ムラが生じな、導光体であることが分かる。 [0032] 図 6は別実施例に係る光散乱パターンを底面側から見た拡大図、図 7は図 6の A— A方向断面図であり、この実施例にあっては光散乱パターンの各形成領域を微細な凹球面 11を稠密状に連続して形成して!/ヽる。 [0031] Further, from FIG. 5 (b), even if the document float is 3 mm, the waveform is almost the same as that of Omm in FIG. From the figure, it can be seen that the intensity ratio does not change so much even if the floating amount of the original increases. In particular, the light guide of the present invention is a light guide that does not cause abnormal unevenness at the position where the main scanning displacement is 15 mm as in the prior art, and does not cause color unevenness. I understand. [0032] Fig. 6 is an enlarged view of a light scattering pattern according to another embodiment as viewed from the bottom side, and Fig. 7 is a cross-sectional view taken along the direction AA of Fig. 6. In this embodiment, each of the light scattering patterns is shown. Form the formation area by continuously forming a fine concave spherical surface 11 in a dense manner!

[0033] 凹球面 11の断面形状の一例としては、直径 0. 09mmの円を 0. 01〜0. 02の範囲で重ねることで形成される深さ 0. 02-0. 03mmの円弧とする。 [0033] As an example of the cross-sectional shape of the concave spherical surface 11, a circular arc having a depth of 0.02 to 0.03 mm formed by overlapping circles having a diameter of 0.09 mm in the range of 0.01 to 0.02 is used. .

[0034] 以下に凹球面 11の深さについて実験した結果を示す。図 8は凹球面 11の元になる球の直径を 30 /ζ πι、凹球面 11の深さを 7〜10 mとした場合、つまり凹球面 11の深さを球の直径の 0. 23-0. 33とした場合の色ムラの度合いを示したグラフであり、図 9は同じ凹球面でも深さを直径の 1Z2 (完全な半球)とした場合の色ムラの度合いを示したグラフである。なお、実験条件として、 Rの LEDを中央に配置したことにより、 Rのデータは常に Bと Gの中間に位置するため図示して!/ヽな!、。 [0034] Results of experiments on the depth of the concave spherical surface 11 are shown below. Figure 8 shows the case where the diameter of the sphere that forms the concave sphere 11 is 30 / ζ πι, and the depth of the concave sphere 11 is 7 to 10 m, that is, the depth of the concave sphere 11 is 0.23 of the diameter of the sphere. Fig. 9 is a graph showing the degree of color unevenness when the depth is 1Z2 (complete hemisphere) even with the same concave spherical surface. is there. As an experimental condition, the R LED is placed in the center, so the R data is always in the middle of B and G!

[0035] 図 8から、凹球面 15の深さを球の直径の 0. 33とした場合には、色ムラ特に LED近傍での色ムラが抑制されており、一方、図 9の場合には、特に LED近傍で色ムラが発生していることがわかる。なお、凹球面 11の深さを球の直径の 0. 23とした場合も、図 8と同様の結果が得られた。 [0035] From FIG. 8, when the depth of the concave spherical surface 15 is 0.33 of the diameter of the sphere, color unevenness, particularly color unevenness in the vicinity of the LED is suppressed, whereas in the case of FIG. It can be seen that color unevenness occurs especially near the LED. When the depth of the concave spherical surface 11 was set to 0.23 of the diameter of the sphere, the same result as in FIG. 8 was obtained.

[0036] これらの図から、凹球面の深さは当該微細凹球面がその一部をなす球の直径の 0. [0036] From these figures, the depth of the concave spherical surface is 0. 0 of the diameter of the sphere of which the fine concave spherical surface is a part.

23以上 0. 33以下とすることで、色ムラ特に LED近傍での色ムラを抑制できることがゎカゝる。 By setting it to 23 or more and 0.33 or less, it is possible to suppress color unevenness, particularly in the vicinity of the LED.

[0037] 図 10 (a)〜（c)は別実施例を示す図 4と同様の図であり、これらの実施例の全体形状 (正面、背面、平面、左右の側面および両端面）は図 3に示した実施例と同一であるので図示は省略する。 FIGS. 10 (a) to 10 (c) are views similar to FIG. 4 showing another embodiment, and the overall shape (front, back, plane, left and right side surfaces and both end surfaces) of these embodiments is as follows. The illustration is omitted because it is the same as the embodiment shown in FIG.

[0038] 図 10 (a)に示す実施例は、光散乱パターン 11となる複数の半球状凹部の密度を導光体の長さ方向において異ならせることで、光反射強度を調整している。また、図 10 (b)及び (c)に示す実施例は入射面の近傍部分に形成する光散乱パターン 11を三角溝または半割円筒溝にて構成し、何れも三角溝または半割円筒溝の軸の方向を、光散乱パターン 11を形成する底面 3bの幅方向（副走査方向）に対し角度を持たせ、且つ隣接する三角溝または半割円筒溝の軸方向が反対方向を向くようにしている。具体的には図 10 (b)では 2つの三角溝または半割円筒溝が X字状をなし、（c)では 2つの三角溝または半割円筒溝がハ字状をなすようにして、る。 In the embodiment shown in FIG. 10 (a), the light reflection intensity is adjusted by making the density of the plurality of hemispherical concave portions to be the light scattering pattern 11 different in the length direction of the light guide. Further, in the embodiment shown in FIGS. 10 (b) and 10 (c), the light scattering pattern 11 formed in the vicinity of the incident surface is constituted by a triangular groove or a half cylindrical groove, both of which are triangular grooves or half cylindrical grooves. The direction of the axis of the light is inclined with respect to the width direction (sub-scanning direction) of the bottom surface 3b forming the light scattering pattern 11, and the axial direction of the adjacent triangular groove or half cylindrical groove is directed in the opposite direction. ing. Specifically, in Fig. 10 (b), two triangular grooves or half-cylindrical grooves are X-shaped, and (c) The two triangular grooves or half-cylindrical grooves are shaped like a letter C.

[0039] このように、個々の三角溝または半割円筒溝は角度依存性がある形状であるが、 2 つ組み合わせることで、角度依存性がなくなる。 [0039] As described above, each triangular groove or half-cylindrical groove has a shape having an angle dependency, but the angle dependency is eliminated by combining the two.

[0040] 更に、図 11は別実施例を示す導光体の要部の斜視図であり、この実施例にあっては光源 10の近傍の導光体両側面 3c, 3dに散乱領域 13, 13を設け、更に両側面 3c , 3dと光散乱パターンを形成した底面 3bとの間に底面 3bで反射した光を出射面 3a に向けて反射する角度の平坦状面取り部 3g, 3hを形成している。 Further, FIG. 11 is a perspective view of the main part of the light guide showing another embodiment. In this embodiment, scattering regions 13 are formed on both side surfaces 3c and 3d of the light guide near the light source 10. 13 is further formed between the side surfaces 3c, 3d and the bottom surface 3b on which the light scattering pattern is formed, and flat chamfered portions 3g, 3h having an angle for reflecting the light reflected by the bottom surface 3b toward the exit surface 3a are formed. ing.

[0041] このように、光源近傍の導光体両側面に散乱領域 13, 13を設けることにより、入射光が撹乱されて出射光の色ムラが低減する。前記散乱領域の形成方法としては、射出成形により微細凹凸を形成してもよいし、白色インキを印刷して形成してもよいし、レーザ光などによって表面を粗らして形成してもよい。 In this way, by providing the scattering regions 13 and 13 on both side surfaces of the light guide near the light source, the incident light is disturbed and the color unevenness of the emitted light is reduced. As the method for forming the scattering region, fine irregularities may be formed by injection molding, white ink may be printed, or the surface may be roughened by laser light or the like. .

[0042] また、所定角度の平坦状面取り部 3g, 3hを形成することで、照度を高めることができる。 In addition, the illuminance can be increased by forming the flat chamfered portions 3g and 3h having a predetermined angle.

図面の簡単な説明 Brief Description of Drawings

[0043] [図 1]本発明に係る導光体を組み込んだライン照明装置を用いた画像読取装置の断面図 FIG. 1 is a cross-sectional view of an image reading apparatus using a line illumination device incorporating a light guide according to the present invention.

[図 2]ライン照明装置の分解斜視図 [Fig.2] Exploded perspective view of line lighting device

[図 3] (a)は本発明に係る導光体の正面図、（b)は背面図、（c)は平面図、（d)は底面図、（e)は左側面図、（f)は右側面図 [FIG. 3] (a) is a front view of a light guide according to the present invention, (b) is a rear view, (c) is a plan view, (d) is a bottom view, (e) is a left side view, (f ) Is right side view

[図 4]本発明に係る導光体の入射面の近傍部分における光散乱パターンの拡大図 FIG. 4 is an enlarged view of the light scattering pattern in the vicinity of the incident surface of the light guide according to the present invention.

[図 5]実施例に示した導光体の主走査変位と光強度との関係を各色ごとに示したダラフであり、（a)は原稿の浮き量が Omm、（b)原稿の浮き量が 3mm、（c)は原稿の浮き量力 Ommと 3mmの場合の光強度比を示す。 [FIG. 5] A graph showing the relationship between the main scanning displacement of the light guide shown in the embodiment and the light intensity for each color. (A) is the document floating amount Omm, (b) the document floating is The amount is 3mm, and (c) shows the light intensity ratio when the document lift force is Omm and 3mm.

[図 6]別実施例に係る光散乱パターンを底面側力見た拡大図 [Fig. 6] Enlarged view of the light scattering pattern according to another embodiment, looking at the bottom side force

[図 7]図 6の A— A方向断面図 [Fig.7] A—A cross-sectional view of Fig. 6

[図 8]凹球面の深さを球の直径の 1Z3 (0. 33)とした場合の色ムラの度合いを示したグラフ [Figure 8] Graph showing the degree of color unevenness when the depth of the concave sphere is 1Z3 (0.33) of the sphere diameter

[図 9]凹球面の深さを球の直径の 1 Z2とした場合の色ムラの度合いを示したグラフ [図 10] (a)〜(c)は別実施例を示す図 4と同様の図 [Figure 9] Graph showing the degree of color unevenness when the depth of the concave sphere is 1 Z2 of the diameter of the sphere [FIG. 10] (a) to (c) are diagrams similar to FIG. 4 showing another embodiment.

[図 11]別実施例を示す導光体の要部の斜視図 FIG. 11 is a perspective view of a main part of a light guide showing another embodiment.

[図 12]光散乱パターンとして三角溝を形成した導光体の主走査変位と光強度との関係を各色ごとに示したグラフであり、（a)は原稿の浮き量力Omm、（b)原稿の浮き量力 S3mm、（c)は原稿の浮き量が Ommと 3mmの場合の光強度比を示す。 [FIG. 12] A graph showing the relationship between the main scanning displacement of a light guide having a triangular groove as a light scattering pattern and the light intensity for each color, (a) is the document floating amount force Omm, (b) Document lift force S3mm, (c) indicates the light intensity ratio when the document lift is Omm and 3mm.

産業上の利用可能性 Industrial applicability

本発明に係る照明装置およびイメージセンサは、コピー機、ファクシミリ等の画像読取装置に組み込まれて有効に利用される。 The illumination device and the image sensor according to the present invention are incorporated in an image reading device such as a copying machine and a facsimile and are effectively used.

Claims

請求の範囲 The scope of the claims

[1] 棒状をなす導光体であって、この導光体は一端面を入射面とし、一側面を出射面とし、他の側面に前記出射面に向力つて光を反射せしめる光散乱パターンが設けられ、この光散乱パターンは凹部または凸部で構成され、この光散乱パターンのうち前記入射面の近傍部分ではパターン形状を出射面以外に向力つても反射する角度依存性のない形状とされ、前記入射面力離れた部分ではパターン形状を出射面に向かつて反射する角度依存性のある形状とされていることを特徴とする導光体。 [1] A light guide having a rod-like shape, the light guide having one end surface as an incident surface, one side surface as an output surface, and the other side surface reflecting light by directing the output surface. A pattern is provided, and this light scattering pattern is constituted by a concave portion or a convex portion, and in the light scattering pattern, in the vicinity of the incident surface, a pattern shape that does not depend on the angle is reflected even if the pattern shape is directed to other than the exit surface. The light guide is characterized in that the pattern shape is an angle-dependent shape that reflects toward the exit surface at a portion away from the incident surface force.

[2] 請求項 1に記載の導光体にお!、て、前記入射面の近傍部分の光散乱パターンの形状は、多数の微細な半球状凹部からなり、前記入射面から離れた部分の光散乱バターンの形状は、パターンを形成した側面の幅方向（副走査方向）を軸方向とする三角溝または半割円筒溝であることを特徴とする導光体。 [2] In the light guide according to claim 1, the shape of the light scattering pattern in the vicinity of the incident surface is composed of a number of fine hemispherical recesses and is a portion separated from the incident surface. The shape of the light scattering pattern is a triangular groove or a half-cylindrical groove whose axial direction is the width direction (sub-scanning direction) of the side surface on which the pattern is formed.

[3] 請求項 2に記載の導光体において、前記入射面の近傍部分の光散乱パターンを構成する多数の微細な半球状凹部は、パターンを形成した側面の長さ方向（主走査方向）において、半球状凹部の形成密度が異なることを特徴とする導光体。 [3] The light guide according to claim 2, wherein a number of fine hemispherical recesses constituting a light scattering pattern in the vicinity of the incident surface are formed in the length direction of the side surface on which the pattern is formed (main scanning method). Direction), the formation density of the hemispherical recesses is different.

[4] 請求項 2に記載の導光体において、前記入射面の近傍部分の光散乱パターンを構成する多数の微細な半球状凹部は連続または分離して形成され、この半球状凹部の深さは当該半球状凹部がその一部をなす球の直径の 0. 23以上 0. 33以下であることを特徴とする導光体。 [4] In the light guide according to claim 2, a large number of fine hemispherical recesses constituting a light scattering pattern in the vicinity of the incident surface are formed continuously or separately, and the depth of the hemispherical recesses The light guide body is characterized in that the hemispherical concave portion has a diameter of 0.23 or more and 0.33 or less of a sphere that forms a part thereof.

[5] 請求項 1に記載の導光体にお!、て、前記入射面の近傍部分の光散乱パターンの形状は、パターンを形成した側面の幅方向に対し斜め方向を軸方向とする三角溝または半割円筒溝であり、前記入射面力離れた部分の光散乱パターンの形状は、バターンを形成した側面の幅方向を軸方向とする三角溝または半割円筒溝であることを特徴とする導光体。 [5] In the light guide according to claim 1, the shape of the light scattering pattern in the vicinity of the incident surface is an axial direction oblique to the width direction of the side surface on which the pattern is formed. The shape of the light scattering pattern of the portion separated from the incident surface force is a triangular groove or a half cylindrical groove whose axial direction is the width direction of the side surface on which the pattern is formed. A light guide characterized by that.

[6] 請求項 5に記載の導光体において、前記入射面の近傍部分の光散乱パターンを構成する三角溝または半割円筒溝は、互いに隣り合う三角溝または半割円筒溝の軸方向が側面の幅方向を基準として反対方向であることを特徴とする導光体。 [6] The light guide according to claim 5, wherein the triangular grooves or half cylindrical grooves constituting the light scattering pattern in the vicinity of the incident surface are axial directions of adjacent triangular grooves or half cylindrical grooves. A light guide characterized in that the direction is the opposite direction with respect to the width direction of the side surface.

[7] 請求項 1に記載の導光体において、この導光体の両側面と底面との間には、底面で反射した光を前記出射面に向けて反射する角度の平坦状面取り部が形成されていることを特徴とする導光体。 [7] The light guide according to claim 1, wherein a flat chamfered portion having an angle for reflecting light reflected by the bottom surface toward the emission surface is provided between both side surfaces and the bottom surface of the light guide. Formed A light guide characterized by that.

[8] 請求項 1に記載の導光体において、前記入射面近傍の導光体の両側面に散乱領域が形成されてヽることを特徴とする導光体。 [8] The light guide according to claim 1, wherein a scattering region is formed on both side surfaces of the light guide near the incident surface.

[9] 請求項 1乃至請求項 8に記載の導光体を組み込んだ照明装置と、この照明装置からの出射光のうち原稿からの反射光をラインイメージセンサに向けて集光せしめるレンズアレイとを備えたことを特徴とする画像読取装置。 [9] An illumination device incorporating the light guide according to any one of claims 1 to 8, a lens array for condensing reflected light from a document out of the light emitted from the illumination device toward a line image sensor, and An image reading apparatus comprising: